---
title: 6.16 Lambda Functions
description: A lambda function is an unnamed function that can be defined directly at the location where it is needed. Lambda expressions provide a concise way to create callable objects without declaring a separate named function. A lambda expression can capture…
url: "https://magenta-tarsier-454184.hostingersite.com/docs/cpp-programming/functions/6-16-lambda-functions/"
updated: "2026-09-06"
category: C++ Programming / Functions
---

# 6.16 Lambda Functions

A lambda function is an unnamed function that can be defined directly at the location where it is needed. Lambda expressions provide a concise way to create callable objects without declaring a separate named function.

A lambda expression can capture variables from its surrounding scope, accept parameters, specify a return type, and contain a function body. Lambdas are commonly used with algorithms and other functions that accept callable objects.

## Source Code

```
#include <iostream>

int main()
{
    auto add = [](int first, int second)
    {
        return first + second;
    };

    int result = add(10, 20);

    std::cout << "Sum: " << result << '\n';

    return 0;
}
```

## Output

```
Sum: 30
```

## Explanation

- `[]` is the **capture clause** of the lambda expression.
- An empty capture clause means that the lambda does not capture variables from the surrounding scope.
- `(int first, int second)` defines the lambda's parameters.
- The statements enclosed within `{}` form the lambda's function body.
- `return first + second;` returns the sum of the two parameters.
- `auto add` stores the lambda in a variable using type deduction.
- `add(10, 20)` invokes the lambda with `10` and `20` as arguments.
- The return type of the lambda is deduced automatically from its `return` statement in this example.
- Lambda expressions can be passed directly to functions that accept callable objects.
- `return 0;` terminates the program successfully.